Hi, Auke -

>At first everything worked fine, but now every time I rebuild the control I have to tell VFP to use that control, and I have to add the controls to my form again, because if I open the form I get the 'class not registered' error message. The same thing if I want to run the application. Running regsrv32 does not help. Fortunately everything is still in test.

This is just a thought, but what do you have set in your Project|Properties|Component tab under Version Compatibility? Have you changed the setting since the rebuilds started breaking? I *think* that you *might* to use binary compatibility while you're testing your control.

HTH